3WF: AP circuit breaker - (Archive)

Following Cessna’s initiative on new 172s (cockpit pic) and a US DOT Safety Alert, the autopilot circuit breaker in 3WF now has a yellow plastic ring around it – which does not mean that the AP is INOP.  The purpose of that ring is to locate and pull it faster in the very unlikely case that all standard AP disconnect methods fail, and you need to transfer control of the aircraft from the AP back to yourself:

  • STANDARD: Press the AP DISC (disconnect) button on the pilot yoke left side
    • Alternative 1: press the AP button on the GMC 507 AP mode controller
    • Alternative 2: briefly move both manual electric trim switches simultaneously in either direction
    • If all above three methods should fail to disengage the AP or a runaway trim then by all means pull the AP circuit breaker (that would be a very rare case though), and hand-fly the plane.

Cessna uses a white ring around the AP circuit breaker, but we could only get a yellow one – which is close enough (also note that we deviated from Cessna’s standard of inexplicably marking the fuel pump switch in the same color as the lights – white – whereas we chose blue, just like the color of the 100LL the fuel pump moves before engine startup).

To use the AP please familiarize yourself with the AFMS and this guide published by Garmin – and of course follow the advice of your CFI.